title: Influence of cerebral venous obstruction on cerebral circulation in humans.
abstract: The influence of cerebral venous obstruction on cerebral circulation was investigated in three patients with cerebral venous and sinus thrombosis in the chronic stage. The xenon Xe 133 intracarotid injection method was used to evaluate the cerebral blood flow (CBF). Values for CBF showed a slight decrease in all patients, despite intact cerebrovascular autoregulation. In two of the three patients, hypercapnia failed to increase CBF, but hyperventilation decreased CBF normally. This phenomenon can be explained on the basis of both failure of the capacitance vessels on the venous side to dilate and an increased intracranial pressure and is not attributable to decreased carbon dioxide reactivity. Long-lasting obstruction of the venous system can lead to a slight reduction in CBF and not affect cerebral autoregulation or CO2 reactivity itself in humans.
mesh_terms: D000293:Adolescent; D000328:Adult; D001794:Blood Pressure; D002245:Carbon Dioxide / Q000502:physiology; D002560:Cerebrovascular Circulation; D006706:Homeostasis; D006801:Humans; D002542:Intracranial Embolism and Thrombosis / Q000503:physiopathology*; D008297:Male; D010101:Oxygen Consumption; D012851:Sinus Thrombosis, Intracranial / Q000503:physiopathology*; D014680:Veins
chemical_list: D002245:Carbon Dioxide